Might future advances in sensor technology reduce or eliminate noise?This is true for very short exposure times, but how short? Can you add some (estimated) values for the different exposures in the example picture. Are we talking about 1 nano second to 10 nano seconds, or are we approaching "normal" camera performance exposure times? I realise this will depend on the amount of light, but take a "normal" indoor scene as an example.

Why are medium format cameras considered superior?I don't understand your question. You're saying that larger is better, point to a link that say S2 has larger sensor than 1DX, and then you jump to a conclusion that this isn't just about size. I don't follow...